Protective coatings for radiation-sensitive elements, especially silver halide layers are well known. Protective coatings have been formulated for both the radiation-sensitive side of the element and the other side of the element. This other side is commonly referred to in the art as the support side or the base side of the element. These coatings are designed to provide a variety of properties such as resistance to abrasion and resistance to solvent attack.
Certain photographic elements have further requirements which must be met by the base side protective overcoat. For example, the base side of the photographic element is often coated with an antistatic layer. The protective coating is applied over the antistatic layer. Frequently, chemicals in a photographic processing solution or in the environment are capable of reacting with the conductive compound in the antistatic layer, thus causing the antistatic layer to lose much of its conductivity. Thus, a protective layer for an element having a base side antistatic layer must be capable of chemically isolating the antistatic layer.
In many photographic processing sequences, the final step is a so-called stabilization step. The solution used in this step varies from process to process. In almost all cases the solution contains a surfactant designed to provide excellent wetting of the emulsion side of the film. Polymeric protective layers such as disclosed in U.S. Pat. No. 4,431,727 comprises a compatible blend of (a) cellulose nitrate and (b) a hydrophobic polymer wherein the hydrophobic polymer has a glass transition temperature of at least about 50.degree. C. The layers are highly hydrophobic. When the stabilizing solution evaporates, a deposit of the surfactant in the form of an objectionable surface haze or scum appears on the protective layer.